14-08-2015 06:10 PM
14-08-2015 06:45 PM - edited 14-08-2015 06:47 PM
I'm guessing that you (and your sister?) have an iPhone?
If so then see here:
Basically with some or all iPhones you have to switch profile when roaming abroad and then switch it back when you return.
This info is probably stored on the SIM which is most likely why your sister's SIM works in your phone but your SIM won't work in her phone (or your own phone).
I don't know why iPhones are so much hassle - other phones (e.g. Android, Windows etc.) don't need this messing...
Hope this helps.
15-08-2015 10:50 AM